Usain Bolt ‘not worried’ heading into showdown with Justin Gatlin

Getty ImagesGoing by times the last two years, Justin Gatlin ought to be a heavy favorite over Usain Bolt in the World Championships 100m final in Beijing.

But even the confident Gatlin cautions those who are sure that Bolt is set to suffer his first global championship 100m defeat Sunday (not counting the 2011 Worlds false start).

This year, Gatlin has repeatedly noted the case of 2012, when Bolt was beaten in the Jamaican Olympic trials on June 29 and entered the London Olympics vincible.

Bolt revved up in the 2012 Olympic semifinals, clocking a casual 9.87 while swerving his head to look at other lanes halfway through the race. Later that night, Bolt ran the second fastest 100m of all time,…